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World records are under threat from male and female runners at the London Marathon on Sunday (3:30 a.m. ET, NBCSN and NBC Sports Gold).

The forecast calls for the warmest London Marathon in its 38-year history (a high Sunday in the low 70s, though likely cooler for the morning start times).

The elite fields, stronger than for last Monday’s Boston Marathon, include the greatest marathoners of this generation — Eliud Kipchoge and Mary Keitany — plus arguably each Kenyan’s top rival at the moment.

In Kipchoge’s last start in London, he missed countryman Dennis Kimetto‘s world record by eight seconds, prevailing in 2:03:05 in 2016. Since, Kipchoge won the Olympic title, had what he deemed his greatest performance in the sub-two-hour (non-record-eligible) event and extended his marathon win streak to seven races over four years in rainy, humid Berlin last September. The 33-year-old has refused to get into world-record talk, telling media he just wants to run “a beautiful race” Sunday.

Credentials from 5000m to marathon make a strong case that Bekele is the greatest runner of all time, ahead of Usain Bolt and Kipchoge. He really started taking aim at the world record after that 2016 Berlin breakthrough. Bekele was runner-up with foot blisters in London last year, nearly three minutes slower than in Germany, and failed to finish his other two marathons in 2017. “To have the records for 5000m to marathon would be something – no one else has done that. I feel like that would make me the greatest ever,” Bekele said, according to marathon organizers.

Farah’s primary goal Sunday is modest in comparison to Kipchoge and Bekele — break the British marathon record of 2:07:13. Farah, repeating in a press conference Tuesday that he is ranked 27th in the world in the distance, said he still intends to go out with the leaders even if they start on world-record pace. It’s his first marathon since switching full-time to road running after last season and his second overall after his 2:08:21 in London four years ago.

Guye Adola, Ethiopia
Second to Kipchoge at 2017 Berlin Marathon in 26.2-mile debut

Adola came out of nowhere to finish 14 seconds behind Kipchoge in Berlin on Sept. 24 in the fastest-ever marathon debut on a record-eligible course, sticking with Kipchoge until the last mile. Afterward, we learned Adola didn’t know he was running until four days before the race and wasn’t meant to start with the elite group. The 27-year-old was second and fifth in half marathons in January and February, not particularly impressive.

Daniel Wanjiru, Kenya
2017 London Marathon winner

Wanjiru won his major marathon debut last year, then returned to London for the world championships on Aug. 6 and was eighth. Neither of those fields was as strong as Sunday’s is shaping up to be. Just 25, Wanjiru will be tested like never before.

The 5-foot-2 mother of two smashed Paula Radcliffe‘s women-only world record by 41 seconds in London last year, clocking 2:17:01. She’ll run with male pacers Sunday in a bid to break Radcliffe’s world record of 2:15:25 from the 2003 London Marathon (the first time since 2003 London has male pacers for the women’s race). Keitany was stunned by Shalane Flanagan at her last marathon in New York City in November but came back in February to lower her half marathon personal best. “I’ve had Paula’s record in mind since I started my career,” the 36-year-old Keitany said.

The Baby-Faced Destroyer is the only woman in the field whose personal best is within two minutes of Keitany’s. There’s reason to believe she can be closer to Keitany than last year (55 seconds behind, and that’s after stopping briefly with two miles left with stomach problems). Dibaba is four years younger than Keitany, with a decorated track background and just one year into her full-time marathon career.

Gladys Cherono, Kenya
2015, 2017 Berlin Marathon winner

The woman with the third-fastest personal best in the field has never raced London and was fifth in her only major marathon outside of Berlin. She was eighth in a half marathon in February, more than two minutes behind Keitany.

Impressive second year as a marathoner in 2017. Chelimo, 28, was born in Kenya but switched to Bahrain in 2015. Though this is her London Marathon debut, her world title came in London in August. She did not impress at the world half marathon championships last month, finishing 14th overall and fifth among runners from Bahrain.

Vivian Cheruiyot, Kenya
Fourth at 2017 London Marathon in 26.2-mile debut
Four Olympic medals in 5000m/10,000m
Four world championships in 5000m/10,000m

Credentials similar to but not quite as impressive as Dibaba in terms of track medals, early marathon experience and age (34 to Dibaba’s 32). Cheruiyot finished more than five minutes behind Keitany and Dibaba in her 26.2-mile debut in London last year. She dropped out of the New York City Half Marathon on March 18 with a breathing problem in the cold weather but insisted she’s healthy for Sunday.